Single Scored Liner - MBN Cat

Discussion in 'Trucks [ Eighteen Wheelers ]' started by underpsi, Jun 28, 2013.

  1. underpsi

    underpsi Road Train Member

    1,266
    289
    Sep 18, 2008
    Toronto, Ont
    0
    Well got our MBN apart again because it had excessive blowby/dead #4 cylinder. This engine was just rebuilt with after market cylinder kits and all 6 holes were counterbored. Exact same Look to the piston and liner that trevor had in his thread http://www.thetruckersreport.com/tr...-eighteen-wheelers/216652-engine-failure.html but the difference is he had multiple cylinder that were scored in a Acert and we only have one cylinder scored on a MBN.

    Not sure if this colouration is the heat marks that Mr.Haney was referring to in trevor's thread, although it is obvious heat issue that scored the cylinder I have no idea why. All 5 other holes look great and the top of the piston in the scored cylinder looks fine as well so I don't think its a bad injector.
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    My first thought after pulling the piston out was that it was a plugged/broken/bent piston cooling nozzle. To the left is a brand new updated nozzle and the right is the nozzle from #4. The old nozzle as no obvious issues I can find at all, both tubes are flowing and not blocked and the curves on the tubes seem consistently the same with the new one. Not to mention for 1 brand new piston cooling nozzle it cost $100 without the bolt!
    [​IMG]

    Another view of the nozzles old to right right and new to the left
    [​IMG]

    What do you guys think? When rebuilt it was done with IPD cylinder packs, pistons, rings, and liners, and IPD gaskets. Injectors are stock MBN 10R1000's and its running a 550hp 6NZ file, also has a brand new stg 1 Cat turbo put on at the time of rebuild less than 20,000 miles ago.
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. dirthaller

    dirthaller Heavy Load Member

    813
    8,601
    Sep 22, 2011
    Coloratah
    0
    Bad injector. ####... I said it!
     
  4. DDS

    DDS Medium Load Member

    519
    177
    May 20, 2008
    Toronto
    0
    By the picture, Old nozzle looks bent, short tube is bent up.
     
  5. billandlori

    billandlori Medium Load Member

    357
    106
    Sep 5, 2010
    Stratford, Ontario, Canada
    0
    That hurts!!

    How does the #4 nozzle alignment compare to the other 5?

    Bill
     
    h50 Thanks this.
  6. truckmechanic

    truckmechanic Medium Load Member

    534
    140
    Jan 14, 2012
    Hi Desert Ca
    0
    Most likely an overfueling injector creating excessive heat
     
  7. Mr. Haney

    Mr. Haney Road Train Member

    2,693
    2,020
    Dec 17, 2008
    0
    Looks bent............LOL...........it is bent

    When I'm referring to the underside of a piston..........that is exactly what I mean. Look at the underside of the firebowl. If it is black and blue, with a build up of burn oil right under the firebowl, then it is being over fueled. The sidewall of the cylinder wall and the piston, will naturally show the signs of heat where the scoring took place on the back side. If the underside of the firebowl doesn't show signs of heat, then it turns into a mechanical problem more with the jets, cylinder wall being out of round or lack of piston to bore clearances. You can also have issues with coolant flow blockages in the cylinder block that is causing a cylinder to run hot................like someone leaving a rag in the block has been know to score a few cylinders.
     
  8. underpsi

    underpsi Road Train Member

    1,266
    289
    Sep 18, 2008
    Toronto, Ont
    0
    Not a good picture as I took them on the back of the checkerplate of my tailgate they are not both sitting at the same angle. If your holding them both in your hand there is not an obvious difference between them.

    I didn't even bother to take a picture of the top of the piston because it looks the same as the other 5 pistons. No obvious signs of overfueling.
     
  9. t800kwopper

    t800kwopper Bobtail Member

    44
    9
    Feb 10, 2009
    Graham,NC
    0
    sorry to see that, good luck gettin back up & runnin:biggrin_255:
     
  10. underpsi

    underpsi Road Train Member

    1,266
    289
    Sep 18, 2008
    Toronto, Ont
    0
    Got some pictures of the top of the piston and the bottom

    [​IMG]

    [​IMG]
     
  11. BullDoggin

    BullDoggin Light Load Member

    183
    55
    Jan 27, 2013
    0
    I think that blue in the underside pic is exactly what Kurt was talking about...
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  • Draft saved Draft deleted